Visible‐Light‐Induced Cycloaddition of α‐Ketoacylsilanes with Imines: Facile Access to β‐Lactams
Jian‐Heng Ye, Peter Bellotti, Tiffany O. Paulisch, Constantin G. Daniliuc, Frank Glorius
Abstract
We report the synthesis of β-lactams from α-ketoacylsilanes and imines, which proceeds via a formal [2+2] photochemical cycloaddition with in situ generation of siloxyketene. This mild and operationally simple reaction proceeds in an atom-economic fashion with broad substrate scope, including aldimines, ketimines, hydrazones, and fused nitrogen heterocycles, affording a variety of important β-lactams with satisfactory diastereoselectivities in most cases. This reaction also features good functional-group tolerance, facile scalability and product diversification. Experimental and computational studies suggest that α-ketoacylsilanes can serve as photochemical precursors by engaging in a 1,3 silicon shift to the distal carbonyl group.